1) To have had sex in the past tense
2) To be doomed to misery in the near future
3) Describing someone who is totally and utterly drunk and/or completely under the influence of one or more drugs beyond the point of comprehension, rationality and all response. They may be puking everywhere and/or behaving abnormally, influenced by whatever's in their body. 'Fucked' is not usually referred to as a pleasant experience.

1) "Dude, Sam fucked Kay last night!!"
2) "Aaagh! Somebody called the cops! We're totally fucked!!"
3) "Dude, he is so completely fucked he doesn't even know what's going on. Help me get him to bed."